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Published on: August 19, 2016

Beta-haemolytic group A streptococci emm75 carrying altered pyrogenic exotoxin A linked to scarlet fever in adults

Hongjun Dong1, Guozhang Xu, Shuhua Li

  • 1Department of Infectious Disease, Ningbo Municipal Center for Disease Control and Prevention, Ningbo 315010, China.

The Journal of Infection
|March 18, 2008
PubMed
Abstract

Insights

A food-borne outbreak of scarlet fever in adults was caused by a specific strain of Group A Streptococcus (GAS) bacteria, identified as emm75. This strain carried a unique version of the speA gene, responsible for the illness.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Genetics

Background:

  • Scarlet fever outbreaks can occur through foodborne transmission.
  • Identifying the specific etiological agent is crucial for outbreak control.

Purpose of the Study:

  • To determine the causative agent of a foodborne scarlet fever outbreak in adults.
  • To characterize the genetic makeup of the responsible pathogen.

Main Methods:

  • Throat swabs were cultured and isolates identified using biochemical methods and automated systems.
  • emm gene and exotoxin genes were amplified via PCR and sequenced.
  • Bioinformatics tools were used for sequence comparison and protein structure prediction.

Main Results:

  • Beta-hemolytic Group A Streptococcus (GAS) emm75 was identified in most patients.
  • All isolates possessed speA and speB genes, with speA showing significant phylogenetic and structural differences from reference strains.
  • Isolates were susceptible to common antibiotics.

Conclusions:

  • Group A Streptococcus emm75, carrying an altered speA gene, was identified as the cause of the adult foodborne scarlet fever outbreak.
  • The genetic variations in speA may contribute to the outbreak's characteristics.

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